Crime-related memory disturbances: The role of stress hormones and neurotransmitters

DSpace/Manakin Repository

Crime-related memory disturbances: The role of stress hormones and neurotransmitters

Kuijlaars, J.A.F.

(2010) Faculty of Medicine Theses

(Master thesis)

Abstract

Claims of memory disturbances for a crime are not unusual in court and in forensic literature, with estimated rates of claimed amnesia (partial or complete memory loss) in 20-40% of, mainly violent, crimes. These claims can have important legal implications, such as incompetency to stand trial, or irresponsibility for a ... read more committed crime. Thus, claiming amnesia might cause quite some personal gain in court when an offender is believed.
However, next to cases of malingered amnesia, true amnesia might occur. True amnesia might be caused by structural brain disease or other factors. Furthermore, some researchers argue that a stress reaction involved in crime might cause certain amounts of amnesia. This latter hypothesis about memory disruptions for a crime is reviewed in this thesis. The central question is: What is the possible influence of (stress) hormones and neurotransmitters on memory for a crime?
In order to answer this question, it is important to note that memory is not a unitary phenomenon, involving long-term, intricate processes. This makes memory vulnerable for many different disturbances of course. As a reaction to threat, the stress response aims at survival via mechanisms involving all parts of the body. However, stress mediators can have negative influences on the brain as well. Memory is one of the brain functions that seems highly vulnerable to these negative effects (but also positive effects, following an inverted U-shaped relationship). One of the seriously impacted brain areas is the hippocampus, which is important in learning and memory, and has the highest expression of stress hormone receptors. High levels of stress hormones and neurotransmitters have been shown to cause structural and functional disruptions of this region. Furthermore, the amygdala, which is involved in emotional memory, might be influenced by stress mediators. Some predisposing factors for negative influences of stress on memory have been described, as well as certain conditions that have to be met to induce these negative effects.
Due to these negative influences of stress on memory, it is not unexplicable that crime-related amnesia can be caused by stress. Memory retrieval might be impaired in offenders, as well as the hippocampus and its functions. Predisposing factors like previous trauma might be related to criminality as well. However, there are inconsistent findings about these proposed mechanisms, which are more elaborately described in the text.
Therefore, it is concluded that stress-induced amnesia cannot account for the larger part of cases of claimed amnesia. Other mechanisms might be involved in causing amnesia for a crime, but malingering of amnesia should definitely not be underestimated. Using various tests to detect malingering, decisions in court might be supported, but, of course, lawyers become smarter as well and might assist their clients to malinger symptoms as good as possible. Therefore, it is very important to take into account that there is a chance of malingering of offenders, witnesses, and victims, but true memory disturbances might occur as well. Continuing research might eventually give justice. show less

Download/Full Text

Not available. The author may have various reasons for not providing access, for instance because it is prohibited by the commissioner of the research, or because the author is conducting further research on the subject.